A gas turbine engine typically includes a fan section, a compressor section, a combustor section and a turbine section. Air entering the compressor section is compressed and delivered into the combustion section where it is mixed with fuel and ignited to generate a high-speed exhaust gas flow. The high-speed exhaust gas flow expands through the turbine section to drive the compressor and the fan section.
The turbine section encounters high temperatures and pressures and is therefore provided with cooling airflow. Cooling airflow can be drawn from the relative cool compressor section and routed around the combustor section to the turbine section. The cooling airflow is drawn through openings in the compressor section that are located between stages corresponding to a desired temperature and pressure for cooling the turbine section. Air flow drawn from the compressor decreases the efficiency of the compressor section and decreases overall thermal efficiency of the engine. Moreover, restrictions in cooling airflow passages that communicate airflow to the turbine section can increase the amount of cooling airflow required to be drawn from the compressor and further reduce engine efficiency.
Accordingly, it is desirable to design and develop improved cooling airflow passages for communicating cooling airflow to increase compressor efficiency and overall engine efficiency.